Keira Knightley has been wearing wigs for years due to hair loss

​​"It got so bad that my hair literally began to fall out of my head...."

In an interview with InStyle, Keira Knightley opened up about the serious toll that constantly changing her hair color for movie roles took on her locks. The regular dyeing was so damaging that her hair began to fall out.

Her limp strands returned to their former glory, and now her hair is thicker and fuller than it ever has been.

While Knightley has been lucky enough to recover her strands, hair thinning is a common issue that many women suffer from. It can be triggered by a number of causes—stress, hormones, hair dye, over-styling, depression, and diet among them.